In order to support multiple SQL vendors (MySQL, PostgreSQL, MS-SQL, etc) Directus has a generalized set of field types allowing for more control over API output (array, json, boolean, etc) and to better define system data (m2o, alias, group, etc). When creating or updating fields within the API, you also send a vendor-specific datatype for more granular DBA control over data storage.

alias – Fields that do not have corresponding column in the database

array – Standard array format in API response

binary – Binary strings limited by its length

boolean – true or false

datetime – A date and time in ISO format, eg: 2018-09-19T14:00:43+00:00

date – Date, eg: 2018-09-19

time – Time, eg: 14:09:22

file – Foreign key to directus_files.id

group – Groups fields together visually, children save group into directus_fields.group